AMOC is weakening because of salinity changes, not temperature. There’s still a lot of glacier ice on Greenland that melt and disrupt the current.
AMOC carries a lot of heat that is not likely to be replaced if it fails. Atmosphere convection doesn’t have the heat capacity, so only logical conclusion is that temperatures in europe must drop. And based on research people have done, it’s not gonna be a small amount.
If you want a fun math (and a little physics) exercise, we can estimate how much heat AMOC carries from the equator to northern europe, and also try to see how much air it’s heating in the atmosphere. From here it gets a bit more complicated as we have to estimate the the incoming solar radiation and earths radiative cooling. But from there you could compare estimated temperatures with and without AMOC heating.
Yeah your just missing two key facts here. One, yeah europe is still getting warmer, AMOC hasn’t collapsed. Two, the conditions for maintaining a convective current are significantly easier than starting one. So if AMOC collapses and Greenland ice stops melting, there’s no guarantee AMOC will restart. And even if it does, it could take centuries.